... in these parameters. The rises in ion concentrations were notable after transfer to 120% SW,whereas urea concentration decreased predominantly following transfer to 80%SW. In elephant fish, we could not find a discrete rectal gland. Instead,approximately 10 tubular structures were located in the wall of post-valvular...

...Susan K. Fellner; Laurel Parker SUMMARY The elasmobranch Squalus acanthias controls plasma osmolality and extracellular fluid volume by secreting a hypertonic fluid from its rectal gland. Because we found a correlation between extracellular Ca 2+ concentration and changes in cytosolic Ca 2+ ([Ca 2...

...David H. Evans; Peter M. Piermarini ABSTRACT The importance of the rectal gland in elasmobranch osmoregulation is well established. The rate of secretion by the gland is under the control of a variety of secretagogues and inhibitors. Early morphological work suggested that a band of smooth muscle...

...Peter M. Piermarini; David H. Evans ABSTRACT Changes in Na + /K + -ATPase activity and abundance associated with environmental salinity were investigated in the gills and rectal gland of the Atlantic stingray Dasyatis sabina . Using a ouabain-specific ATPase assay and western blotting, we found...

... by active Na+ extrusion via the pump and passive K+ exit via a channel. Intracellular [Cl − ] is raised above electrochemical equilibrium and exits into the lumen when the apical Cl − channel opens. Cl − secretion is accompanied by a passive paracellular flow of Na+. The tubules of the rectal glands...

...T. J. Shuttleworth; J. L. Thompson ABSTRACT Perfusion and sodium secretion parameters were measured in the isolated rectal gland of Scyliorhinus canicula L. perfused at in vivo pressures, and the effect of stimulation of secretory activity by cyclic AMP and theophylline on these parameters...

...D. Erlij; R. Rubio ABSTRACT We measured the venous and arterial pressure, as well as the rate of secretion and content of cyclic AMP and high energy phosphate compounds, of the rectal gland of the anaesthetized dogfish, Squalus acantinas (L.). Intravenous infusion of isotonic solutions produced...

...Franklin H. Epstein; Jeffrey S. Stoff; Patricio Silva ABSTRACT Secretion of chloride from blood to lumen is accomplished in the rectal gland of elasmobranchs by a process of secondary active transport involving the co-transport of Cl − with Na + across the basolateral membranes of rectal gland...

...T. J. Shuttleworth ABSTRACT Perfusion flow rate in the isolated elasmobranch rectal gland, perfused at in vivo pressures, was measured in Scyliorhinus canicula L. and Squalus acanthias L. Flow through the secretory parenchyma of the gland was reduced in the presence of concentrations...